The central purpose of the mutant and Transgenic Rodent Core (MTRC) is to provide Shock Center-affiliated investigators with aged mice of genotypes that provide otherwise unavailable opportunities to investigate the basic biology of the aging process and the pathophysiology of age-related disease states. Aged animals of standard (usually inbred or F1 hybrid) genotypes are routinely available through the NIA. and the UM Pepper Center's Core Facility for Aged Rodents (CFAR) make available genetically heterogeneous mice produced by a four-way cross breeding scheme. A facility such as the MTRC proposed for the Shock Center does not exist anywhere in the country. The Shock Center MTRC is specifically dedicated to exploiting for gerontologic research the wide range of mutant and transgenic mice currently available but not yet studied in an aging context. The Specific Aims of the MRTC are to produce aged mice of a variety of genotypes as model systems for the analysis of aging and age-related physiological changes, to aid Shock Center investigators in constructing new transgenic founder animals for analyses of the genetic basis for age-related pathophysiology and provide supervision and technical assistance to NIAC. The MTRC will be housed in the North Ingalls Animal Colony (NIAC) which is located on the 11th floor of the north Ingalls Building immediately above the IoG. The NIAC is run jointly by the IoG and the Reproductive Sciences Program with Co-Directors (John Faulkner and michael Welsh, respectively) one from each unit. The NIAC is run on a day-to-day basic by a half-time manager and a full-time animal care technician. We propose to add a second animal care technician to handle the increased work-load imposed by the MTRC mice. The MRTC will be directed by Sally Camper. Dr. Camper will chair a Core Oversight Committee consisting of Dr. Robert Dysko (Veterinary Consultant), Dr. Richard Miller, Dr. David Burke, and Dr. John Faulkner.